Process for breaking petroleum emulsions



Patented July 1, 1952 UNE'E'ED STATES PATENT OFFHQE PROCESS FOR BREAKING PETROLEUM EMULSIONS No Drawing. Application March 5, 1951, 7

Serial No. 214,001

9 Claims.

This invention relates toprocesses or procedures particularly adapted for preventing, breaking, or resolving emulsions of the water-in-oil type and particularly petroleum emulsions.

Complementary to the above aspect of the invention herein disclosed is my companion invention concerned with the new chemical products or compounds used as the demulsifying agents in said aforementioned processes or procedures, as well as the application of such chemical products, compounds, or the like, in various other arts and industries, along with the method for manufacturing said new chemical products or compounds which are of outstanding value in demulsification. See my co-pending application, Serial No. 214,002, filedMarch 5, 1951.

My present invention provides an economical and rapid process for resolving petroleum emulsions of the water-in-oil type that are commonly referred to as cut oil, roily oil, emulsified oil, etc., and which comprise fine droplets of naturally-occurring waters or brines dispersed in a more or less permanent. state throughout the oil which constitutes the continuous phase of the emulsion.

t also provides an economical and rapidprocess for separating emulsions which have been prepared under controlled conditions from mineral oil, such as crude oil and relatively soft waters or weakbrines. Controlled emulsification and subsequent demulsification, under the conditions just mentioned are of significant value in removing impurities, particularly inorganic salts, from pipeline oil.

Demulsification as contemplated in the present application includes the preventive step of cominingling the demulsifier with the aqueous component which would or might subsequently become either phase of the emulsion in the absence of such precautionary measure. Similarly, such dem-ulsifier may be mixed with the hydrocarbon component.

The present invention is concerned with a process for breaking petroleum emulsions by means of fractional esters obtained from a polycar-boxy acid and oxypropylated 4,4, dihydroxydiphenyl sulfone. Such4,4 dihydroxydiphenyl sulfone is treated with propylene oxide so that the molecular weight based on the hydroxyl number, is in the range of approximately 1,000 to approximately 5,000. Such oxypropylated derivatives are invariably xylene-soluble and waterinsoluble. When the molecular weight, based'on thehydroxyl value, is modestly. in excessof 1,000, for instance, 1,200 to 1,500,and higher, the oxy-' 2 propylated product is kerosene-soluble. My preference is to use an oxypropylated 4,4 dihydroxydiphenyl sulfone which is kerosene-soluble as an intermediate for combination with polycarboxy acids as hereinafter described. Such esterification procedure yields fractional esters which serve for the herein described purpose.

As hereinafter pointed out, however, one need not necessarily use the 4,4 sulfone but for the reason that the 2,4 isomer is the obvious functional equivalent and is just as satisfactory this applies, also, to a mixture of the two which is more economical to use as described subsequently.

As is well known, 4,4 dihydroxydiphenyl sulfone is a chemical compound having the following formula:

If for convenience the sulfoneis indicated thus:

HOR'-OH the product. obtained by oxypropylation may be indicated thus:

with the proviso that n and n represent whole numbers, which, added together, equal a sum varying from 15 to 80, and the acidic ester obtained by reaction of the polycarboxy acid may be indicated thus:

l (H0OC), "R( J(OCaHuMOR/O(CQH Q),. &R(COOHM" whichthe characters have their previous sign1ficance, and n" is a whole number not over 2 and R is the radical of the polycarboxy radical:

COOH

acid and a polyalkylene glycol in which the ratio of equivalents of polybasic acid to equivalents of polyalkylene glycol is in the range of 0.5 to 2.0, in which the alkylene group has from 2 to 3 carbon atoms, and in which the molecular weight of the product is between 1,500 to 4,000.

Similarly, there have been used esters of dicarboxy acids and polypropylene glycols in which 2 moles of the dicarboxy acid ester have been reacted with one mole of a polypropylene glycol having a molecular weight, for example, of 2,000 so as to form an acidic fractional ester. Subsequent examination of what is said herein in comparison with the previous example as well as the hereto appended claims will show the line of delineation between such somewhat comparable compounds. Of greater significance, however, is. what is said subsequently in regard to the structure of the parent diol as compared to polypropylene glycols whose molecular weights may vary from 1,000 to 2,000. I

In the instant application the initial material is 4,4 dihydroxydiphenyl sulfone which, although readily soluble inboiling water, is almost insoluble in cold water. It is merely a matter of definition', or rather temperature of water, to characterize the compound as Water-insoluble or soluble. For convenience, so there will be no misunderstanding, it will be referred to as water-- insoluble.

Numerous water-insoluble compounds susceptible to oxalkylation, and particularly to oxyethylation, have been oxyethylated so as to produce eifective surface-active agents which, in some instances, at least have also had at least modest demulsifying property. Reference is made to similar monomeric compounds having a hydrophobe group containing, for example, 8 to 32 carbon atoms and a reactive hydrogen atom, such as the usual acids, alcohols, alkylated phenols, amines, amides, etc. In such instances invariably the approach was to introduce acounterbalancing effeet by means of the addition of a hydrophile group, particularly ethylene oxide, or, in some instances, glycide, or perhaps a mixture of both hydrophile groups and hydrophobegroups, as, for example, in the introduction of propylene oxide along with ethylene oxide. In another type of material, a polymeric material such as a resin, has been subjected to reaction with an alkylene oxide including propylene oxide. In such instances certain derivatives obtained from polycarboxy acids' have been employed.

Obviously, thousands and thousands of combinations, starting with hundreds of initial waterinsoluble materials, are possible. Exploration of a large number of raw materials, has yielded. only a few which appear to be commercially practical and competitive with available demulsifying agents. 4,4 Dihydroxy diphenyl sulfone happens to be one such compound. On the other hand, a somewhat closely comparable compound, pp.'-Bisphenol having the following structure:

does not seem to yield analogous derivatives of nearly the effectiveness of 4,4 dihydroxy'diphenyl sulfone. The reason or reasons for this difference, is obviously obscure and merely a matter of speculation.

Of course, this much is obvious. in regard to. the sulfonev as compared with. p, p-Bisphenol which contains another element in addition to carbon,

' hydrogen and oxygen, i .e., sulfur. Furthermore,

the oxygen atoms attached to sulfur in the sulfone present an electronic structure not usually present in the absence of sulfur or a comparable element,

Exhaustive oxypropylation renders a water-soluble material water-insoluble. Similarly, it ren ders a kerosene-insoluble material kerosene-soluble; for instance, reference has been made to the fact that this is true, for example, using polypropylene glycol 2000. Actually, it is true with polypropylene glycol having lower molecular weights than 2000. These materials are obtained by the oxypropyl'ation of a water-soluble kerosene-insoluble material, i. e., either water or propylene glycol.

Just why certain different materials which are water-insoluble to start with and which presumably are rendered more water-insoluble by exhaustive oxypropylation (if such expression more water-insoluble has significance), can be converted into a valuable surface-active agent and particularly a valuable demulsifying agent by reaction with a polycarboxy acid which does not particularly affect the solubility one way or the other-depending upon the selection of the acidis unexplainable.

For convenience, what is said hereinafter will be divided into three parts:

Part '1 is concerned with the oxypropylation derivatives of 4,4 dihydroxy diphenyl sulfone;

Part 2 is concerned with the preparation of esters from the aforementioned diols or dihydroxylated compounds;

Part 3 is concerned with the use of the products herein described as demulsifiers for. breaking water-in-oil emulsions.

In actual manufacture it is simplest to make a sulfonewhich is a mixture of 2 isomers, to wit,

4,4 sulfone and 2,4. dihydroxydiphenyl sulfone. For sake of simplicity all references to the 4,4 sulfone are intended to include the 2,4 sulfone or mixtures. The preparation of the mixtures is described in Journal of-the Chemical Society,

1949, pages 2854-56. The article is entitled 424'- and 2:4'-Dihydroxydiphenyl Sulphones. The authorsare Hinkel and Summers. By way of illustration the following brief excerptv is included in substantially verbatim form:

Sulphuric acid 98% (13 cc., 1 mol.) was added to phenol (53 g., 2-5 mols.) contained in a distilling flask fitted with a thermometer dipping into the reactionmixture and areceiver attached to the side-arm. The temperature of the mixture was quickly raised. to and maintained there for 6 hours during which some water was evolved. The temperature. was then maintained at 195-200 for a. further 6 hours during which more water and a little phenol distilled. Whilst still molten, the contents of the. flask were poured into water and steam-distilled to remove the excess of phenol. Suflicient boiling water was added to efiect complete dissolution. The solution was decolorized with charcoal, fitered, and left to cool, whereupon a mass: of crystals separated (43 g.). Concentration of the aqueous nitrate to a very small bulk gave la further yield of crystals, M. P. ca. (6 g.) (total yield, 49 g., 86%). consists of 4:4'-dihydroxydiphenyl sulphone containing approx. 16% of the 2:4'-isomeride.

The two isomerides. were separated as'described later.

The product If, inv the above: experiment, the initial mix- 7' was 78% and they contained approx. 24% of the 2:4-isomeride. The final aqueous filtrate from the sulphones wasneutralised with aqueous am Separation of Isomers.--The well-dried crude product was dissolved in the minimum quantity.

of boiling acetone. Warm benzene (twice the volume of acetone used) was then added and the mixture set aside overnight in a cool place.

A considerable quantity of solvate was deposited as prismatic crystals (A). These were removed and heated to 120 to remove the combined benzene (Found: loss on heating, 23.9. Cl2Hl0o4S, CsI-Is requires C6H6,23.8% The resulting 4:4'dihydroxydiphenyl sulphone, which melted at 246-247 still contained traces of the 2:4-isomeride and was again subjected to the acetonebenzene treatment. The crystals so obtained were added to boiling water, whereupon they dissolved With brisk evolution of benzene. The aqueous solution on cooling yielded 4:4'-dihydroxydiphenyl sulphone as very long needles, M. P. 249-5". Further similar treatment with acetone-benzene did not raise the M. P. The dimethoxy-derivative, prepared in the usual manner and crystallised from alcohol, melted at 132 (Machek and Haas give M. P. 130-5"). The dibenzoate, prepared in the usual way, crystallised from alcohol in needles, M. P. 248-5 (Found: C, 68.3; H, 4.05; S, 7.0. C24H1806S requires C, 68.1; H, 3.9; S, '7.0%).

PART 1 For a number of well known reasonsequipment, whether laboratory size, semi-pilot plant size, pilot plant size, or large scale size, is not, as a rule, designed for a particular alkylene oxide. Invariably and inevitably, however, or particularly in the case of laboratory equipment and pilot plant size, the design is such as to use any of the customarily available alkylene oxide, 1. e., ethylene oxide, propylene oxide, butylene oxide, glycide, epichlorohydrin, styrene oxide, etc. In the subsequent description of the equipment it becomes obvious that it is adapted for oxyethylation as well as oxypropylation. I

Oxypropylations are conducted under a wide variety of conditions not only in regard to presence or absence of catalyst and the kind of catalyst, but also in regard to the time of reaction, temperature of reaction, speed of reaction, pressure during reaction, etc. For instance, oxyalkylations can be conducted at temperatures up to approximately 200 C. with pressures in about the same range up to about 200 pounds per square inch. They can be conducted also at temperatures approximating the boiling point of water or slightly above, as, for example, 95 to 120 C. Under such circumstances the pressure will be less than 30 pounds per square inch unless some special procedure is employed as is sometimes the case, to wit, keeping an atmosphere of inert gas such as nitrogen in the vessel during the reaction. Such low-temperature-low reaction rate oxypropylations have been described very completely in U. S. Patent No. 2,448,664, to H. R. Fife, et al., dated September '7, 1948. Lowtemperature-low pressure oxypropylations are particularly desirable where the compound being subjected to oxypropylation contains one, two,

or three points of reaction only, such as monohydric alcohols, glycols and triols.

Since low-pressure-low-temperature reaction speed oxypropylations require considerable time,

for. instance, 1 to .7 days of 24 hours each. to,

complete the reaction, they are conducted as a rule whether:on a laboratory scale, pilot plant scale, or. large scale, so as to operate automaticallyr The prior figure of seven days applies especially tolarge-scale operations. I have used conventional equipment with two added automatic features:

(a) A solenoid-controlled valve which shuts off the propylene oxide in event that the temperature gets outside a predetermined and set range, for instance, to C.; and

(2)) Another solenoid valve which shuts off the propylene oxide (or for that matter ethylene oxide if it isbeing used) if the pressure gets beyond a predetermined range, such as 25 to 35 pounds.

Otherwise, the equipment is substantially the same as is commonly employed for this purpose where the pressureof reaction is higher, speed of reaction is higher, and time of reaction is much shorter. In such instances such automatic con-v trols are not necessarily used.

Thus, in preparing the various examples I have found it particularly advantageous to use laboratory equipment or pilot plant which is designed to permit continuous oxyalkylation, whether it be oxypropylation or oxyethylation. With certain obvious changes the equipment can be used also to permit oxyalkylation involving the use of glycide where no pressure is involved except the vapor pressure of a solvent, if any, which may have been used as a diluent.

As previously pointed out, the method of using propylene oxide is the same as ethylene oxide. This point is emphasized only for the reason that the apparatus is so designed and constructed as to use either oxide.

The oxypropylation procedure employed in the preparation of the oxyalkylated derivatives has been uniformly the same, particularly in light of the fact that a continuous automatically-controlled procedure was employed. In this procedure the autoclave was a conventional autoclave made of stainless steel and having a capacity of approximately 15 gallons and a working pressure of one thousand pounds gauge pressure. This pressure obviously is far beyond any requirement as far as propylene oxide goes unless there is a reaction of explosive violence involved due to accident. The autoclave was equipped with the conventional devices and openings, such as the variable-speed stirrer operating at speeds from 50 R. P. M. to 500 R. P. M.; thermometer well and thermocouple for mechanical thermometer; emptying outlet; pressure gauge, manual vent line, charge hole for initial reactants; at least one connection for introducing the alkylene oxide, such as propylene oxide or ethylene oxide, to the bottom of the autoclave; along with suitable devices for both cooling and heating the autoclave, such as a cooling jacket, and preferably, coils in addition thereto, with the jacket so arranged that it is suitable for heating with steam or cooling with water and further equipped with electrical heating devices. Such autoclaves are, of course, in essence, small-scale replicas of the usual conventional autoclave used in oxyalkylation procedures. In some instances in exploratory preparations. an autoclave having a smaller capacity, for. instance, approximately /2 liters in one; case and about 1% gallons in another case, was

used.

Continuous operation, or substantially continuous operation, was achieved by the use ofv a separate container to hold the alkylene oxide being employed, particularlypropylene' oxide; In

conjunction with the smaller autoclaves the container consistsessentially ofpalaboratory bomb having a capacity of aboutone-half gallon, or somewhat in excess thereof. In some instances a larger bomb was used, to wit,. one having a capacity of about one gallon. equipped, also, with an inlet for: charging, and an eductor tube going to the bottom of the container so as to permit discharging of alkylene oxide in the liquid phase to the autoclave. A bomb having a capacity of about 60 poundswas used in. connection with the -gallon. autoclave.

Other conventional equipment consists; of course, of the rupture disc, pressure gauge, sight feed.

glass, thermometer connection for nitrogen for pressuring bomb, etc. The bomb was placed on a scale during use. bomb and the autoclave were flexible stainless steel hose or tubing so that continuous weighings could be made without breaking ormaking any connections. This applies also to the nitrogen line which was used to pressure the-bomb reser voir. other. usual conventional, procedure or addition which provided greater safety was used, of course, such as safety glass, protective screens, etc;

Attention is directed again to whathas been i sibly 98 C. Similarly; the pressure was held.

at approximately pounds within a 5-pound variation one way or the other but might drop to practicallyzero, especially where no solvent such as xylene wasv employed. The speed of reaction was comparatively slow under such conditions as compared with oxyalkylations at 200 C.

Numerous reactions were conducted in which the 5 time varied from one day (24hours), up to three.

days (72 hours), for completion of the finalv member of a series. In some instances, the re.-

action may take place in considerably less time,

i. e., 24 hours or less, as far as a partial oxypropylation is concerned. The minimum time recorded was about a 4-hour period in a single step. Reactions indicated as. being, complete in 10 hours may have been complete in a. lesser period of time in light of the. automatic equipment employed. This applies, also where" the reactions were complete in a shorter. period of time, for instance, 4 to 5 hours. Inthe addition of propylene oxide, in the autoclave equipment as far as possible the valves were set so all the: propylene oxide, if fed continuously, would beadded at a rate so that the predetermined amount would react within the first lShours of. the 24- hour period or two-thirds of any shorter period.

This meant that if the reaction was interrupted.

This. bomb was The connections between the To the extent that it was required any sure.

automatically for a period of time for pressure to drop or temperature to: drop, the predetermined amount of oxide would'still be added, in most instances, well within. the. predetermined time period. Sometimes. where the addition was a comparatively small amount in a 10-hour period there would be an unquestionable speeding up of. the reaction by simply repeating the examples andusing 2, 3, or 4 hours instead of 5 hours.

When operating at a comparatively high temperature,.for instance, between 150 to 200 C., an unreacted alkylene oxide, such as propylene oxide, makes its presence, felt in the increase in pressureor the consistency of a. higher pres- I-Iowever, at a low enough temperature it may happen that the, propylene oxide goes in as a liquid; If so; and. if. it remains unreacted, there is, of course, an inherent danger and appropriate steps must be taken to safeguard against this possibility; if need be, a sample must be withdrawn and examined for unreacted propylene oxide. One obvious procedure, of course, is to oxypropylate at a modestly higher temperature, for. instance, at to C. Unreacted oxide affects determination of the acetyl or hydroxyl value of the hydroxylated compound obtained.

The higher the molecular Weight of the compound, i. e., towards the latter stages of reaction, the longer the time required to add a given amount of oxide. One possible explanation is that the molecule: being: larger the opportunity for random reaction is decreased. Inversely, the lower the molecularweight' the faster the reactiontakes place. For this reason, sometimes at least, increasingthe concentration of the catalyst'does not appreciably speed up the reaction particularly when the product subjected to oxyalkylation has acomparatively high molecular weight. However, as has been pointedout previously, operating ata low pressure and a low temperaturev even in large scale operations as much as aweek. or. ten days time may lapse to obtain some of thehigher molecular. weight derivatives from monohydric or dihydric materials.

In a number of operations the counterbalance. scale or dial scale holding the propylene oxide.

1 use on larger equipment than laboratory size autoclaves, to wit, on semi-pilot plant or pilot plant size-as well ason large-scale size. This final stirring period is intended to avoid the presence of.

unreacted oxide.

In. this sertv of. operation, of. course, the temperature range was controlled automatically by either use of cooling water, steam, or electrical heat, so as to raise or lower the temperature.

The pressuring, of the propylene oxide into the i reaction vessel was also automatic insofar that the feed stream. was set. for a slow continuous run. which was shut off. in case the pressure passed a predetermined point as previously set out. All the points of design, construction, etc., were convention-a1 including the gases, check valves and entire equipment. As far as I am aware at least'two' firms, and possibly three, specialize in autoclave equipment such as I have employed in the laboratory, and are prepared to furnish equipment of this same kind. Similarly,

' 9 pilot plant equipment is available. This point is simply made as a precaution in the direction of safety. Oxyalkylations, particularly involving ethylene oxide, glycide, propylene oxide, etc.,

10 perature and pressure were concerned were the same as in Example 2a, preceding. The oxide was added in 4 hours; The rate was approximately 400 grams per hour.

should not be conducted except in equipment specifically designed for the purpose. Example 1116 grams of the reaction mass identified as Example Example 111, preceding, equivalent to initially 193 The starting material was commercial 4,4 digrams of q 711 grams of the oxide '19 hydroxydiphenyl sulfone The particular auto grams of caust c soda, and 193 grams of solvent, clave employed was one having a capacity of a were reacted with 348 grams of propylene oxide. little Over a gallon The speed of the stirrer The conditions of temperature and pressure were could be varied from 150 to 350 R. P. M. The the t as Exampie precedmg- The t autoclave was charged with 500 grams of required to add the oxide was 4 hours. The oxlde mm, 50 grams caustic Soda, and 500 grams 15 was addedat the rate of about 125 grams per lene. The caustic soda was finely powdered and hour 0 1 so was the sulfone. The xylene added was just Exampfi 5a sufiicient to produce a slurry. The reaction pot 476 grains of the reaction mass identified as was flushed out with nitrogen. The autoclave I Example 111, preceding, equivalent initially to was sealed and the automatic devices adjusted 46.1 gramsof sulfone, 379 grams of oxide, 4.6 for injecting 1850 grams of propylene oxide in a grams of caustic soda, and 46.1 grams of solvent, 6-hour period. The rate was set for about 400 to were reacted with 669 grains of propylene oxide. 450 grams per hour. The pressure was set for a The conditions of reaction, as far as temperature maximum of 35 pounds per square inch. This and pressure were concerned, were the same as meant that the bulk of the reaction could take in Example 2a, preceding. The time required to place, and probably did take place, at a lower add the oxide was 8 hours. The rate was at about pressure. The comparatively low pressure was 150 grams per hour. the result of the fact that considerable catalyst In this particular series of examples the oxywas present and also the reaction time was fairly propylations covered the range indicated. I long, i. e., 6 hours. As indicated, the addition of have conducted the same experiments using the propylene oxide was comparatively slow and, 2,4 isomer or mixtures prepared in the manner more important, the selected temperature was described previously. Similarly, in other series I 110 C., or slightly above the boiling point of wahave continued oxypropylations so the theoretter. The initial introduction of propylene oxide ical molecular weights were approximately 9,000 was not started until the heating devices had to 10,000 with the hydroxyl molecularweights raised the temperature to above 108 C. At the between 3,500 and 4,500. completion of the reaction a sample was taken What has been said herein is presented in tabuand oxypropylation proceeded as in Example 2a, 'lar form in Table 1,'immediately following, with following. This same example was duplicated some added information as to molecular weight and portions used for subsequent Examples 3a, 40 and as to solubility of the reaction product in 4a, and 5a, as noted below. water, xylene and kerosene.

TABLE-1- Composition before Composition at end 7 t ir 1 Time EX'NO' Sulfone Oxide Cata- Theo.- Sulfone Oxide Catalanai 3 3 lbs. sq Hrs. Amt, Amt, lyst, Mol Amt., Amt, lyst, min. in.

grs. grs. grs. Wt. grs. grs. grs.

Example 2a Examples 1a through 5a were insoluble in wa- 535 grams of the reaction mass identified as soluble m Xylene; Example was Example 1a, preceding, equivalent to initially 96 soluble 1n kerosene, and Examples 2a through 5a grams of the sulfone, 333 grams of the oxide, 10 were 50mm? m kerosenegrams of the caustic Soda, and 96 grams of SOL In each instance there was present at the start vent were reacted with 1331 grams of propylene of the oxypropyla-tion an amount of solvent oxide The reaction temperature was Slightly (xylene) equal in weight to the amount of sulfone. higher than in Example 1a, to Wit, 5 Q The Ordinarily in the initial oxypropylation of a maximum pressure as in Example 1a was 35 simple compound such as ethylene glycol or propQundS per square inch The t required to 35 Dylene glycol, the hydroxyl molecular weight is introduce the oxide was 10 hours. It was introapt to approximate the theoretical molecular duced at about the rate f grams per hour weight based on completeness of reaction if oxypropylation is conducted slowly and at a com- Exampze. paratively low temperature, as described. In this 584 grams of the reaction mass identified as 704 instance, however, this does not seem to follow as Example 1a, preceding, equivalent to initially 104 it is noted in the preceding table that the point grams of sulfone, 366 grams of'propylene oxide, where the theoretical molecular weightis approx- 10 grams of caustic soda, and 104 grams of solimately 3,000 the hydroxyl molecular weight is vent, were reacted with grams of propylene only about one-half this amount. This generalioxide. The conditions of reaction as far as tem- 7 5 zation does not necessarily apply where there are more hydroxyls present, and in the present instance the results are somewhat peculiar when compared with simple dihydroxylated materials as described or with phenols.

The fact that such pronounced variation takes place between hydroxyl molecular weight and theoretical molecular Weight based on completeness of reaction has been subjected to examine-- tion and speculation but no satisfactory rationale has been suggested. When a nitrogen-containing compound is present, such as in the oxypropylation of acetamide or polyamine, the situation becomes even more confused.

One suggestion has been that one hydroxyl is lost by dehydration and that this ultimately cause a break in the molecular in such a way that two new hydroxyls are formed. This is shown after a fashion in a highly idealized manher in the following way:

F IEI I I In the above formula-s the large is obviously not intended to signify anything except the cen tral part of a large molecule, whereas, as far as a speculative explanation is concerned, one need only consider the terminal radicals as shown. Such suggestion is of interest only because it may be a possible explanation of how an increase in hydroxyl value does take place which could be interpreted as a decrease in molecular weight. This at the most slightly more viscous than ordinary polypropylene glycols, with a slight amber tint.

This color, of course, could be removed, if desired, by mean of bleaching clays, filtering chars, or,

the like. The products were slightly alkaline due to the residual caustic soda. The residual basicity due to the catalyst would be the same if sodium methylate had been employed.

Needless to say, there is no complete conversion of propylene oxide into the desired hydroxylated compounds. This is indicated by the fact that the theoretical molecular weight, based on a statistical average, is greater than the molecular weight calculated by usual methods on basis of acetyl or hydroxyl value. This is true even in the case of a normal run of the kind noted previously. It is true also in regard to the oxypropylation of simple compounds, for instance, pentaerythritol, sorbitol, or the like, which do not show the abnormal characteristics sometimes noted in the oxypropylaticn of TMC (tetramethylolcyclohexanol) Actually, there is no completely satisfactory method for determining molecular weights of these types of compounds with a highdegree of accuracy when the molecular weights exceed 2,000. In some instances, the acetyl value or hydroxyl value serves as satisfactorily as an index to the molecular weight as any other procedure, subject to the above limitations, and especially in the higher molecular weight range. If any difficulty is encountered in the manufacture of the esters as described in Part 2, the stoichiometrical amount of acid or acid compoundsbould be taken which corresponds to "the indicated acetyl or 'hydroxyl value. This matter has been discussed in the literature and is a matter of common knowledge and requires no further elaboration. In fact, it is illustrated b some of the examples appearing in the patent previously mentioned. I M

. PARrB As previously pointed out, the-present invention is concerned with acidic esters obtained from the oxypropylated derivativesdescribed in Part 1, immediately preceding," and polycarboxy acids, particularly dicarboxy acids such as adipic acid, phthalic acid, or. anhydride, 'succinic acid, diglycollic acid, sebacic acid, azel'eic acid, aconitic acid,- maleic acid or anhydride, 'citraconic acid or anhydride, maleic acid or anhydride adducts, as obtained by thepiels- Alder reaction from products such as maleic *anhydride, and cyclepentadiene. Such acids should be heat-stable so they are not decompo'sed during esterification. They may contain as-many as 3.6 carbon atoms,

as, for example, the acids obtained by dimeriza tion of unsaturated fatty acids, unsaturated monoearboxyflfatty acids, or unsaturated monocarboxy acids having 18 carbon atoms. Reference to the acid in the hereto appended claims obviously includes the anhydrides or any other obvious equivalents; My preference, however, is

touse polycarbony acids having not over-8 carbon procedure is employed. On a laboratory scale one can employ a resin pot of the kind described in U. $.Patent No. 2,499,370, dated March '7, 1950,

to DejGroote & Keiser, and particularl with one more openin to permit the use of a porous spreader if hydrochloric acid gas is to be used as a catalyst. Such device or absorption spreader consists of minute alundum thimbles which are connected to a'glass tube. One can add a sulfonic acid such as para-toluene sulfonic acid as a catalyst. There is some objection to this because in some instances there is some evidence that this acid catalyst tends to decompose or rearrange heat-oxypropylated compounds, and particularly likely to do so if the esterification temperature is too high. In the case of .polycarboxy acids such as diglycollic acid, which is strongly acidic, there is no need to add any catalyst. The use of hydrochloric gas has one advantage over para-toluene sulfonic acid and that is that at the. end of the reaction it can be removed by flushing out with nitrogen, whereas there is no reasonably convenient means available of removing the paratoluene 'sulfonic acid or other sulfonic acid employed. If hydrochloric acid is employed one need only pass the gas through at an exceedingly slow rate so as tokeep the reaction mass acidic. Only atrace' of acid need be present. I have employed hydrochloric acid gas or the aqueous acid itself: to eliminate the initial basic material. My preference, however, is to use no catalyst whatsoever .ud to insure complete dryness of the diol as described in the final procedure just preceding Table 2.

The products obtained in Part 1, preceding, may contain a basic catalyst. As a general procedure, I have added an amount of half-concentrated hydrochloric acid considerably in excess of what is required to neutralize the residual catalyst. oughly and allowed to stand overnight. It is then filtered and refluxed with the Xylene present until the water can be separated in a phase-separating trap. As soon as the product is substantially free from water the distillation stops. This preliminary step can be carried out in the flask to be used for esterification. further deposition of sodium chloride during the reiiux stage, needless to say, a second filtration may be required. In any event, the neutral or If there is any The mixture is shaken thor slightly acidic solution of the oxypropylated'.

derivatives described in Part 1 is then diluted further with sufficient xylene ,decalin, petroleum solvent, or the like, so that one has obtained produces a half-ester from an anhydride such as phthalic anhydride, no water is eliminated. However, if it is obtained from diglycollic acid, for example, water is eliminated. All such procedures are conventional and have been so thoroughly described in the literature that further I.

consideration will be limited to a few examples and a comprehensive table.

Other procedures for eliminating the basic residual catalyst, if any, can be employed. For example, the oxyalkylation can be conducted in absence of a solvent or the solvent removed after oxypropylation. Such oxypropylation end product can then be acidified with just enough concentrated hydrochloric acid to just neutralize the residual basic catalyst. To this product one can then add a small amount of anhydrous sodium sulfate (sufiicient in quantity to take up any water that is present) and then subject the mass to centrifugal force so as to eliminate the dehydrated sodium sulfate and probably the sodium chloride formed. The clear, somewhat viscous, straw-colored amber liquid so obtained may contain a small amount of sodium sulfate or sodium chloride, but in any event, is perfectly acceptable for esterification in the manner described. 7

It is to be pointed out that the products here described are not polyesters in the sense that there is a plurality of both diol radicals and acid radicals; the product is characterized by .155

having only one diol radical.

In some instances, and in fact, in many instances, I have found that in spite of the dehydration methods employed above a mere trace of water still comes through, and that this mere trace of water certainly interferes with the acetyl or hydroxyl value determination, at least when a number of conventional procedures are used and may retard esterification particularly where there is no sulfonic acid or hydrochloric acid present as a catalyst. Therefore, I have preferred to use the following procedure: I have employed about 200 grams of the diol compound, as described in Part 1, preceding; I have added about 60 grams of benzene, and then refluxed this mixture in the glass resin pot using a phase-separating trap until the benzene carried out all the water present as water of solution or the equivalent. Ordinarily this refluxing temperature is apt to be in the neighborhood-of 130 to possibly 150 C. When all this water or moisture has been removed I also withdraw approximately 20 grams or a little less benzene and then add the required amount of a car:- boxy reactant and also about 150 grams of a high boiling aromatic petroleum solvent. These solvents are sold by various oil refineries, and, as far as solvent effect, act as if they were almost completely aromatic in character. Typical distillation data in the particular type I have employed and found very satisfactory is the following:

I. B. P., 142 50 m1., 242 C. 5 mL, 200 C. i m1., 244 C. 10 ml., 209 C. 1111., 248- C. 15 ml.', 215 C. m1., 252 C. 20 1111., 216 C. ml., 252 C. 25 ml., 220 C. ml., 260 C. 30 ml., 225 C. ml., 264 C. 35 ml., 230 C. ml., 270 C. 40 ml., 234 C. ml., 280 C. 45 m1., 237 C. ml., 307 C.

After this material is added, refluxing is continued and, of course, is at a high temperature, .to wit, about to C. If the carboxy re-. actant is an anhydride, needless .to say, no water of reaction appears; if; the carboxy reactant is an acid water of reaction should appear and should be eliminated at the above reaction tern perature If it is not eliminated, I simply sep-v arate out another 10 to 20 cc. of. benzene by means of the phase-separating trap and thus raise the temperature to or C., or even to 200 C., if need be. My preference is not to go above 200 C. l

The use of such solvent is extremely satisfactory, provided one does not attempt to remove the solvent subsequentlyexcept by vacuum dis tillation, and provided there is no objection to a little residue. Actually, when these materials are used for a purpose such as demulsification the solvent might just as well be allowedto remain. If the solvent is to be removed by distillation, and. particularly vacuum distillation, then the high boiling aromatic petroleum solvent might well be replaced by some more expensive solvent such as decalin or an alkylated decalin which has a rather definite or close range boiling point. The removal of the solvent, of course, is purely a conventional procedure and requiresno elaboration.

In the appended table Solvent #7-3, which appears in all instances, is a mixture of 7 volumes of the aromatic petroleum solvent previously described and 3 volumes of benzene. This was used, or a similarmixture, in the manner previously described. In a large number of similar examples decalin has been used but it is my preference to use the above mentionedmixture,

and particularly with the preliminary step of re- TABLE '2 M01. EX NO Theo. 15;??? Actual Wt. Amtof 3 EX: k010i of Hyd M' droxyl HY] Based a Polycarboxy Rcactant carboxy Acld Ester Cmpd of V of droxy on mp Reactant' 11.0 H Value Actual (grs. gm

1, 025 109. 119. 5 940 213 so. 5 1,025 109. 5 119. 5 940 207 50. 0 1, 025 109. 5 119. 5 940 200 41. c 1, 025 109. 5 119. 5 940 200 53. 0 3, 995 28. 0 46. 0 2, 440 200 22. 1 3, 995 23. 0 45. o 2, 440 206 21. 2 3, 995 28.0 40. 0 2, 440 209 29. s 3, 995 28. 0 40. 0 2, 440 200 24. 2 3, 995 28.0 40. 0 2, 440 209 15.21 3, 995 23. 0 45. 0 2, 440 s 18. 9 a, 095 36. 3 c4. 2 1, 750 20a 31. 5 3, 095 30. 3 e4. 2 1, 750 203 29. 2 3, 095 36. 3 64. 2 1, 750 20s 25. 4 3,095 35.3 54.2 1,750 202 2.0.5 1, 415 79. 4 79.0 1,420 206 Diglycohc Acid- .18. 8 1, 415 79.4 79.0 1, 420 20s Oxalic ACld. 36.5 1, 415 79.4 79. 0 1, 420 203 MaleidAnhyd. 2s. 0 1, 415 79. 4 79. 0 1, 420 200 Pl1t11a11c Anhy 43. 0 5, 178 21. 77 47. 4 2,370 201 Diglycohc ACKL 22. 8 5, 178 21. 7 47. 4 2, 370 203 Oxallc Acid 21. 6 5,173 21.7 47.4 2,370 5 200 Phthalic Anhyd. 25.0 5,178 21. 7 47. 4 2, 370 201 Male1c Anhyd 10. 7

TABLE 3 hr low temperatures and long time of reaction,

there are formed certain compounds Whose com- Maximum 4 ositions are still obscure. Such side reaction Ex. No.0f Acid g 1 Esterifica- 83? p d t {T b t, Stant a To ort o Ester 10 vent (even tion tioneam) (00) pro uc s can con iru e a sue p p p, of the final cogenenc reaction mixture. Var1ous suggestions have been made as to the nature of 266 i 2 2% these compounds, such as being cyclic polymers 2g of propylene oxide, dehydration products with 263 i 6 the appearance of a vinyl radical, or isomers of propylene oxide or derivatives thereof, 1. e., of an 236 155 aldehyde, ketone, or allyl alcohol. In some in- 33 g stances, an attempt to react the stoichiometric 225 2 amount of a polycarboxy acid with the oxypropyl- 132 1 4 1 ated derivative results in an excess of the car- 234 22 6 boxylated reactant for the reason that apparentit, 146 1 49 ly under conditions of reaction less reactive hy- 2 g droXyl radicals are present than indicated by the 229 153 3% III: hydroxyl value. Under such circumstances there fig fig? is simply a residue of the carboxylic reactant it? 155 g which can be removed by filtration, or, if desired, 218 153 the esterification procedure can be repeated The procedure for manufacturing the esters has been illustrated by preceding examples. If, for any reason, reaction does not take place in a manner that is acceptable, attention should be directed to the following details:

(a) Becheck the hydroxyl or acetyl value of the oxypropylated products of the kind specified, and use a stoichiometrically equivalent amount of acid;

(b) If the reaction does not proceed with reasonable speed, either raise. the temperature indicated or else extend the period of time up to 12 or 16 hours, if need be;

(c) If necessary, use of paratcluene sulfonic acid, or some other acid as a catalyst; and

(d) If the esterification does not produce a clear product, a check should be made to see if an inorganic salt such as sodium chloride or sodium sulfate is not precipitating out. Such salt should be eliminated, at least for exploration experimentation, and can be removed by filtering.

Everything else being equal, as the size of the molecule increase and the reactive hydroxyl radical represents a smaller fraction of the entire molecule, thus more difficulty is involved in obtaining complete esterification.

Even under the most carefully controlled conditions of oxypropylation involving comparativeusing an appropriately reduced ratio of carboxylic reactant.

Even the determination of the hydroxyl value and conventional procedure leaves much to be desired due either to the cogeneric materials pre viously referred to, or, for that matter, the presence of any inorganic salts or propylene oxide. Obviously, this oxide should be eliminated.

The solvent employed, if any, can be removed from the finished ester by distillation, and particularly vacuum distillation. The final products or liquids are generally from almost Water White or pale straw to a light amber in color, and show moderate viscosity. They can be bleached with bleaching clays, filtering chars, and the like. However, for the purpose of demulsification or the like, color is not a factor and decolorization is not justified.

In the above instances I have permitted the solvents to remain present in the final reaction mass. In other instances I have followed the same procedure, using decalin or a mixture of decalin or benzene in the same manner and ultimately removed all the solvents by vacuum distillation.

f PART 3 Conventional demulsifying agents employed in the treatment of oil field emulsions are used as such, or after dilution with any suitable solvent, such as water, petroleum hydrocarbons, such as benzene, toluene, xylene, tar acid oil, cresol, anthracene oil, etc. Alcohols, particularly aliphatic alcohols, such as methyl alcohol, ethyl alcohol, denatured alcohol, propyl alcohol, butyl alcohol, hexyl alcohol, octyl alcohol, butyl alcohol, hexyl alcohol, octyl alcohol, etc., may be employed as diluents. Miscellaneous solvents such as pine oil, carbon tetrachloride, sulfur dioxide extract obtained in the refining of petroleum, etc., may be employed as diluents. Similarly, the material or materials employed as the demulsifying agent of my process may be admixed with one or more of the solvents customarily used in connection with conventional demulsifying agents. Moreover, said material or materials may be used alone or in admixture with other suitable well known classes of demulsifying agents.

It is well known that conventional demulsifying agents may be used in a water-soluble form, or in an oil-soluble form, or in a form exhibiting both oiland water-solubility. Sometimes they may be used in a form which exhibits relatively limited oil-solubility. However, since such reagents are frequently used in a ratio of l to 10,000, or 1 to 20,000, or 1 to 30,000, or even 1 to 40,000, or 1 to 50,000 as in desalting practice, such an apparent insolubility in oil and water is not significant because said reagents undoubtedly have solubility within such concentrations. This same fact is true in regard to the material or materials employed as the demulsifying agent of my process.

In practicing my process for resolving petroleum emulsions of the water-in-oil type, a treating agent or demulsifying agent of the kind above described is brought into contact with or caused to act uponthe emulsion to be treated. in any of the various apparatus now generally used to resolve or break petroleum emulsions with a chemical reagent, the above procedure being used alone or in combination with other demulsifying procedure, such as the electrical dehydration process.

One type of procedure is to accumulate a volume of emulsified oil in a tank and conduct a batch treatment type of demulsiflcation procedure to recover clean oil. In this procedure the emulsion is admixed with the demulsifier, for example, by agitating the tank of emulsion and slowly dripping demulsifier into the emulsion. In some cases, mixing is achieved by heating the emulsion while dripping in the demulsifier, depending upon the eonvection currents in the emulsion to produce satisfactory admixture. In a third modification of this type of treatment, a circulating pump withdraws emulsion from, c. g., the bottom of the tank, and reintroduces it into the top of the tank, the demulsifier being added, for example, at the suction side of said circulating pump.

In a second type of treating procedure, the demulsifier is introduced into the well fluids at the well-head or at some point between the Wellhead and the final oil storage tank, by means of an adjustable proportioning mechanism or proportioning pump. Ordinarily, the flow of fluids through the subsequent lines and fittings suffices to produce the desired degree of mixing of demulsifier and emulsion, although in some instances additional mixing devices may be introduced into the flow system. In this general procedure, the system may include various mechanical devices for withdrawin free water, separating entrained water, or accomplishing quiescent settling of the chemicalized emulsion.

l Heating devices may likewise be incorporated in any of the treating procedures described herein.

A third type of application (down-the hole) of demulsifier to emulsion is to introduce the demulsifier either periodically or continuously in diluted or undiluted form into the well and to allow it to come to the surface with the well fluids, and then to flow the chemicalized emulsion through any desirable surface equipment, such as employed in the other treating procedures. This particular type of application is decidedly useful when the demulsifier is used in connection with acidification of calcareous oilbearing strata, especially if suspended in or dissolved in the acid employed for acidification.

In all cases, it will be apparent from the foregoing description, the broad process consists simply in introducing a relatively small proportion of demulsifier into a relatively large proportion of emulsion, admixing the chemical and emulsion either through natural flow or through special apparatus, with or without the application of heat, and allowing the mixture to stand quiescent until the undesirable water content of the emulsion separates and settles from the mass.

The following is a typical installation:

A reservoir to hold the demulsifier of the kind (diluted or undiluted) is placed at the well-head where the efliuent liquids leave the well. This reservoir or container, which may vary from 5 gallons to 50 gallons for convenience, is connected to a proportioning pump which injects the demulsifier dropwise into the fluids leaving the well. Such chemicalized fluids pass through the flowline into a settling tank. The settlin tank consists of a tank of any convenient size, for instance, one which will hold amounts of fluid produced in 4 to 24 hours (500 barrels to 2,000 barrels capacity), and in which there is a perpendicular conduit from the top of the tank to almost the very bottom so as to permit the incoming fluids to pass from the top of the settling tank to the bottom, so that such incoming fluids do not disturb stratification which takes place during the course of demulsification. The settling tank has two outlets, one being below the water level to drain off the water resulting from demulsification or accompanying the emulsion as free water, the other being an oil outlet at the top to permit the passage of dehydrated oil to a second tank, being a storage tank, which holds pipeline or dehydrated oil. If desired, the conduit or pipe which serves to carry the fluids from the well to the settling tank may include a section of pipe with bafiles to serve as a mixer, to insure thorough distribution of the demulsifier throughout the fluids, Or a heater for raising the temperature of the fluids to some convenient temperature, for instance, to F., or both heater and mixer.

Demulsiflcation procedure is started by simply setting the pump so as to feed a comparatively large ratio of demulsifier, forinstance, 1:5,000. As soon as a complete break or satisfactor demulsification is obtained, the pump is regulated until experience shows that th amount of demulsifler being added is just suflicient to produce clean or dehydrated oil. The amount being fed at such stage is usually 1:10,000, 1115,000, 120,000, or the like.

In many instances, the oxyalkylated products herein specified as demulsifiers canbe conveniently used without dilution. However, as previously noted, they may be diluted as desired with any suitable solvent. For instance, by mix-.

teristics of the oxyalkylated product, and, of

course, will be dictated, in part, by economic considerations, i. e., cost.

As noted above, the products herein described may be used not only in diluted form, but also may be used admixed with some other chemical demulsifier.

Having thus described my invention what I claim as new and desire to secure by Letters Patent, is:

1. A process for breaking petroleum emulsions of the water-in-oil type, characterized by sub- .iecting the emulsion to the action of a demulsifier including hydrophile synthetic products; said hydrophile synthetic products being characterized by the following formula:

in which R. is the radical of a member of the class selected from 4,4 dihydroxydiphenyl sulfone, 2,4 dihydroxydiphenyl sulfone and a mixture of the two isomers; n and n are numerals with the proviso that n and n equal a sum varying from to 80, and n" is a whole number not over 2, and R is the radical of the polybasic acid.

in which n" has its previous significance, and with the further proviso that the parent dihydroxylated compound prior to esterification be water-insoluble.

2. A process for breaking petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifier including hydrophile synthetic products; said hydrophile synthetic products being characterized by the following formula:

0 0 (HOOC),.-R%(OCaHu),.ORO(C3H@O),. &R(COOH),1" in which R is the radical of a member of the class selected from 4,4 dihydroxydiphenyl sulfone, 2,4 dihydroxydiphenyl sulfone and a mixture of the two isomers, n and n are numerals with the proviso that n and n equal a sum vary-- 20 J'ecting the emulsion to the action of a demulsifier including hydrophile synthetic products; said hydrophile synthetic products being characterized by the following formula in which R is the radical of a member of the class selected from 4,4 dihydroxydiphenyl sulfone, 2,4 dihydroxydiphenyl sulfone and a mixture of the two isomers; n and n are numerals with the proviso that n and 72' equal a sum varying from 15 to 80, and n" is a whole number not over 2, and R is the radical of the polybasic acid oooHm' in which n" has its previous significance; said polycarboxy acid having not over 8 carbon atoms; and with the further proviso that the parent dihydroxylated compound prior to esterification be water-insoluble, and kerosene-soluble.

4. A process for breaking petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifier including hydropliile synthetic products; said hydrophile synthetic products being characterized by the following formula:

II I H00o Ru ooaHonoR'o oamowcmooon) in which R is the radical of a member of the class selected from 4,4 dihydroxydiphenyl sulfone, 2,4 dihydroxydiphenyl sulfone and a mixture of the two isomers; n and n are numerals with the proviso that n and n equal a sum varying from 15 to 80, and R is the radical of the polybasic acid coon said dicarboxy acid having not over 8 carbon atoms; and with the further proviso that the parent dihydroxylated compound prior to esterthe dicarthe 'dicarthe dicarthe dicar- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Blair Aug. '7, 1951 Number 

1. A PROCESS FOR BREAKING PETROLEUM EMULSIONS OF THE WATER-IN-OIL TYPE, CHARACTERIZED BY SUBJECTING THE EMULSION TO THE ACTION OF A DEMULSIFIER INCLUDING HYDROPHILE SYNTHETIC PRODUCTS; SAID HYDROPHILE SYNTHETIC PRODUCTS BEING CHARACTERIZED BY THE FOLLOWING FORMULA: 